Module 8 - Lymphatic System Flashcards
In comparison to veins, lymphatic vessels:
1. have overlapping endothelial cells that allow the passage of large materials
2. have smaller diameters and lumens
3. absorb more proteins and carbohydrates from the GI tract
4. are not anchored to the surrounding tissues; thus, they have great flexibility
- have overlapping endothelial cells that allow the passage of large materials
The _______ collects lymph from both sides of the body inferior to the diaphragm.
thoracic duct
Lymph is transported through a network of increasingly larger lymphatic vessels. What is the correct order of these, from smallest diameter to largest diameter?
Capillaries - vessels - trunks - ducts
Compared to blood capillaries, lymphatic capillaries:
are more permeable
The lymphatic system functions to maintain normal blood volume and eliminate local variations in the:
composition of interstitial fluid
Lymphatic capillaries:
1. are only located around vital organs
2. are interlaced with blood capillaries (and arterioles and venules) of the cardiovascular system are interlaced with blood capillaries (and arterioles and venules) of the cardiovascular system
3. fill by increases in the interstitial pressure rather than a pump (e.g., the heart)
4. are vessels where interstitial fluid can enter the lymphatic system
5. have collagen fibers to anchor them to surrounding tissue
6. have cuboidal endothelial cells
2, 3, 4, 5
The cells of the lymphatic system are collectively known as:
lymphocytes
Which of the following statements are true:
1. Plasma cells secrete antibodies
2. B cells are lymphocytes that produce antibodies
3. NK cells are the body’s first line against viruses and some types of cancer
4. NK cells are lymphocytes that produce antibodies
5. T cells mature in the thymus
6. T cells are lymphocytes that produce antibodies
1, 2, 3, 5
What are the primary lymphoid organs:
bone marrow and thymus
Which of the following statements are true:
1. tonsils are primary lymphoid organs
2. tonsils are most active in children
3. swelling of the tonsils is an indication of an active immune response
4. tonsils are found in the small intestine
5. tonsils are collections of lymphoid nodules
2, 3, 5
Mucosa-associated lymphoid tissue (MALT):
is important for immune responses to ingested substances
Vessels
arteries, veins, capillaries
Lymphatic capillaries
-are extremely permeable, allowing larger molecules and excess fluid from interstitial spaces to enter the lymphatic vessels
-Closed-ended tubes interspersed around blood capillary beds
-Receive fluid from interstitial fluid in connective tissue
-Overlapping endothelial cells act as one-way valves
(clefts between endothelial cells)
Collecting lymphatic vessels
Have the same three tunics as veins, but the collecting vessels have thinner walls and more internal valves, and they anastomose more.
Lymphatic trunks
The superficial and deep lymphatics eventually merge to form this larger lymphatic vessel; drains lymph from the lymphatic vessels
Lymphatic ducts
right lymphatic duct and thoracic duct
Right lymphatic duct
-Deep to the right clavicle
-Returns lymph from the right side of the head and neck, right upper limb and the right side of the thorax
Thoracic duct
-begins just inferior to the diaphragm
-begins as a saclike structure called the cisterna chyli
-collects lymph from most of the body
Lymphatic System
- associated with the immune system to such a degree that the two systems are virtually indistinguishable
-system of vessels, cells, and organs that carries excess fluids to the bloodstream and filter pathogens from the blood
Lymph
contains a liquid matrix and white blood cells
Lymphedema
An accumulation of interstitial fluid due to lymphatic drainage issue or
lymphatic failure
Lymphatic Cells (Lymphocytes)
are the primary cells of adaptive immune responses; consist of T, B, and NK cells
T-Cells
-thymus-dependent cells
-cell mediated immunity
-do NOT secrete antibodies
-Recognize antibodies on infected cells
-Secrete chemical messengers
-Destroy cells infected with intracellular pathogen
B-Cells
-bone marrow–derived cells
-Generate diverse antibodies (secrete antibodies)
- isolation and destruction of invading bacteria and viruses.
NK Cells
-aka natural killer cell
-Among the first line of defense
-Destroy virally infected cells/certain cancerous cells
Lymphatic Organs
-Separated from surrounding tissue by a fibrous capsule
-include lymph nodes, thymus gland, spleen
Afferent lymphatic vessels
Vessels that bring lymph draining from connective tissue into a lymph node en route to the blood.
Lymph nodes
-function to remove debris and pathogens from the lymph
-site of adaptive immune responses mediated by T cells, B cells, and accessory cells of the adaptive immune system
-site of adaptive immune responses mediated by T cells, B cells, and accessory cells of the adaptive immune system
Efferent lymphatic vessels
Cells and lymph fluid that leave the lymph node may do so by this set of vessels
Thymus
-a bilobed organ found in the space between the sternum and the aorta of the heart
-connective tissue holds the lobes closely together but also separates them and forms a capsule.
Spleen
-major secondary lymphoid organ
-highly vascularized
-fragile organ without a strong capsule and is dark red due to its extensive vascularization
Red pulp
-80%
-Contains mostly erythrocytes, platelets, macrophages, and some plasma cells
-Functions in filtration of blood
-consists of reticular fibers with fixed macrophages attached, free macrophages, and other cells typical of the blood, including some lymphocytes
White pulp
-“cuffs” of lymphoid tissue, lymphocytes, and macrophages
-Functions heavily in adaptive immunity
Lymphatic nodules
-Lymphocytes aggregated within a supporting framework of reticular
fibers
-Wall of segments of the digestive tract
-Nodules have a germinal center, which contains the lymphocytes
Mucosa-associated lymphatic tissue (MALT)
-consists of an aggregate of lymphoid follicles directly associated with the mucous membrane epithelia
-lymphatic tissue found in mucous membranes that line passageways open to the outside world; these include the respiratory, gastrointestinal, urinary, and reproductive tracts
Tonsils
lymphoid nodules located along the pharynx’s inner surface and are important in developing immunity to oral pathogens
Aggregated lymphoid nodules (Peyer’s patches)
-a type of MALT in the small intestine, are especially important for immune responses against ingested substances
-contain specialized endothelial cells called M (or microfold) cells that sample material from the intestinal lumen and transport it to nearby follicles so that adaptive immune responses to potential pathogens can be mounted
Appendix
-A similar process occurs involving MALT in the mucosa and submucosa of the appendix
-A blockage of the lumen triggers these cells to elicit an inflammatory response that can lead to appendicitis.
